Tire monitoring system and method

Abstract

Sensor and method for determining operating states associated with one or more tires. The operating state of the tire can be determined based on one or more measures environmental conditions of the tire(s). For example, a controller can be configured to determine a change in one or more environmental conditions, including determining, for example, a rate-of-change value, a variance value, a standard deviation, or the like. The rate-of-change, variance, and/or standard deviation values can be compared to one or more threshold values to determine the operating state(s) associated with the tire(s). The environmental condition can include, for example, acceleration of the tire, pressure of the tire, and/or temperature of the tire. The operating state can be, for example, a filling state indicative of the tire being inflating, and/or a drive state indicative of the tire rotating about its axle.

What is claimed is: 
     
       1. A monitoring sensor, comprising:
 a sensor configured to generate a signal indicative of (i) rotation of a tire, and (ii) a measured gas-flow produced vibration of the tire; and 
 a controller configured to determine, based on the signal, a filling state of the tire while the tire is in a non-rotating state during which the tire is being inflated or deflated, and 
 wherein the determining includes:
 determining an environmental condition based on a variance value associated with the signal; and 
 comparing the determined variance value to a threshold value to determine the filling state. 
 
 
     
     
       2. The monitoring sensor of  claim 1 , further comprising:
 determining a rate-of-change value of the gas-flow produced vibration, 
 wherein the comparing further comprises comparing the rate-of-change value to a rate-of-change threshold value. 
 
     
     
       3. The monitoring sensor of  claim 1 , wherein the sensor is an acceleration sensor configured to measure an acceleration resulting from the gas-flow produced vibration of the tire that is generated by gas entering or exiting the tire. 
     
     
       4. The monitoring sensor of  claim 1 , wherein the sensor is configured to measure the gas-flow produced vibration caused by gas entering or exiting the tire, the determining of the filling state of the tire being based on the measured vibration caused by the gas entering or exiting the tire. 
     
     
       5. The monitoring sensor of  claim 4 ,
 wherein the determining of the variance value associated with the signal comprises determining a variance value of the measured gas-flow produced vibration; and 
 wherein the comparing of the determined variance value of the gas-flow produced vibration comprises comparing the variance value of the measured gas-flow produced vibration to the threshold value. 
 
     
     
       6. The monitoring sensor of  claim 1 , further comprising:
 a second sensor configured to measure a second environmental condition of the tire and to generate a second signal corresponding to the measured second environmental condition, 
 wherein the controller is further configured to determine the filling state based on the signal and the second signal. 
 
     
     
       7. The monitoring sensor of  claim 6 , wherein the determining of the filling state further comprises:
 determining the second environmental condition based on a second variance value associated with the second signal, and 
 comparing the second variance value to a second threshold value, 
 wherein the determining of the filling state is further based on the comparison of the variance value to the threshold value and the comparison of the second variance value to the second threshold value. 
 
     
     
       8. The monitoring sensor of  claim 7 , wherein the second environmental condition is a pressure of the tire, and
 wherein the second sensor is a pressure sensor configured to measure the pressure of the tire as the second environmental condition. 
 
     
     
       9. The monitoring sensor of  claim 1 , further comprising a pressure sensor configured to measure a pressure of the tire,
 wherein the controller is further configured to adjust a sampling rate of the pressure sensor based on the acceleration signal to reduce the power consumption of the pressure sensor. 
 
     
     
       10. A monitoring method, comprising:
 generating a signal indicative of (i) rotation of a tire, and (ii) a gas-flow produced vibration of the tire; 
 determining a variance of the gas-flow produced vibration based on the signal; 
 comparing the variance to a threshold value; and 
 determine a filling state of the tire based on the comparison while the tire is in a non-rotating state during which the tire is inflated or deflated. 
 
     
     
       11. The monitoring method of  claim 10 , further comprising:
 determining a rate-of-change value of the gas-flow produced vibration; and 
 wherein the comparing further comprises comparing the rate-of-change value to a variance threshold value. 
 
     
     
       12. The monitoring method of  claim 10 , wherein the generated signal is indicative of an acceleration resulting from the gas-flow produced vibration of the tire that is generated by gas flowing in or out of the tire. 
     
     
       13. The monitoring method of  claim 10 ,
 wherein the generated signal is indicative of a measured acceleration resulting from the gas-flow produced vibration of the tire that is caused by gas entering or exiting the tire; and 
 wherein the determining the filling state of the tire is based on the measured acceleration. 
 
     
     
       14. The monitoring method of  claim 13 ,
 wherein determining the variance of the gas-flow produced vibration comprises determining a variance value of the measured acceleration; and 
 wherein the comparing comprises comparing the variance value to the threshold value. 
 
     
     
       15. The monitoring method of  claim 14 , further comprising:
 measuring an environmental condition of the tire based on determining a second variance value; 
 comparing the second variance value to a second threshold value; and 
 determining the filling state associated with the tire based on the comparison of the variance value to the threshold value and a comparison of the second variance value to the second threshold value. 
 
     
     
       16. The monitoring method of  claim 15 , wherein the environmental condition is pressure of the tire. 
     
     
       17. A monitoring device, comprising:
 a sensor configured to generate an acceleration signal indicative of (i) rotation of the tire, and (ii) a measured gas-flow produced vibration of the tire; and 
 a controller configured to determine a rate-of-change value or a variance value based on the acceleration signal, and a filling state of the tire while the tire is in a non-rotating state during which the tire is inflated or deflated based on the determined rate-of-change value or the variance value. 
 
     
     
       18. The monitoring sensor of  claim 17 , wherein the gas-flow produced vibration is generated by a gas passing through a valve of the tire or the gas passing through a hole in the tire, a rim, or a seal formed between the tire and the rim. 
     
     
       19. The monitoring sensor of  claim 17 , further comprising a pressure sensor configured to measure a pressure of the tire,
 wherein the controller is further configured to adjust a sampling rate of the pressure sensor based on the acceleration signal to reduce the power consumption of the pressure sensor.